Pneumatic tool.



Np. 853,416'. Y PATENTED MAY 14', V1907.

' 0. W. MEADOWCROFT, SE. y.

y .PNEUMATIG TnoL.

APPLICATION FILED DEO. 26. 1906.

' THE nonxisreas co. wAsmNcrqN, De c4 CHARLES W. MEADOWCROFT, SR., OF PHILADELPHIA, PENNSYT "VAN,

PNEUMATIC TOOL.

A Specification of Letters Patent.

Patented May 14, 190'?.

Application filed December 26, 1906. Serial No. 349.421.

To @ZZ whom it may concern:

Be it known that I, CHARLES W. MEADOW- cRoF'r, Sr., a citizen of the United States, residing at Frankford, in the city and county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improveobjects, as stone, and the like.

The object of this invention is to provide a tool of the character above indicated which, by reason of its marked simplicity and novelty in details of construction, and the reduction in number of its operating parts to a minimum, may be conveniently and cheaply manufactured, as for commercial purposes; which shall embodyl compound features of construction, including a reciprocating striking-piston of' maximum effective area, thereby materially enhancing the eiiiciency of the tool as a-whole; which shall be durable, positive in operation, and ordinarily suitable for hand-manipulation on the part of the user; and which shall possess certain well-defined advantages over prior analogous devices.

The invention consists in the novel combinations, parts and details of construction whereby, together with the novel disposition and relative arrangement of said parts, the attainment of the foregoing object is rendered practicable, all of which will be hereinafter more specifically described and set forth in the appended claims.

The invention is clearly illustrated in the accompanying drawings, wherein like reference-numerals denote corresponding parts throughout the several views, and as to the latter:

Figure l is a side elevation of a pneumatic tool embodying my said improvements, a portion of the wall of the casing or main cylinder thereof being broken away to disclose certain interior details, and particularly the reciprocating striking-piston therein under reverse adjustment. Fig. 2 is a central, longitudinal section of the device, the strikingpiston being shown in the position it occupies under direct adjustment, as for a striking effect, and partly in section to disclose certain details interior thereof. Fig. 3 is a front end view of the construction shown in Fig. 1. Fig. 4 is a view in perspective of the reciprocating, striking-piston, detached from the general construction. Fig. 5 is a detail sectional view, showing detached from the generalconstruction, the subsidiary cylinder made use of, the section being taken centrally and longitudinally thereof. Fig. 6 is an end view of said subsidiary cylinder.

In a general sense my present invention comprises a main casing or cylinder; a subsidiar cylinder iiXed. wit-hin the main cylinder, forming a distribution chamber, and having opposing inlet ports whereby, respectively, communication is established between said distribution chamber' and the interior of said main cylinder, the latter having a in ain, power-medium supply-passage communicating primarily with said distribution chamber, and suitable, opposing exhaust ports 5 anda compound, reciprocating, striking-pistoi'i, the latter, in its reciprocating movements, controlling alternately said opposing inlet ports and said opposing exhaust ports, and inversely the inlet ports with respect to the exhaust ports,`or vice versa, and being movable under the introduction to and exhaustion from said main cylinder, accordingly, of a power-Huid, preferably air under pressure, at opposite sides thereof.

Having reference to the accompanying drawings, 2 denotes a main casing or cylinder, the front ortion of whose bore is enlarged and threat ed to receive a tubular chuck or nose-piece 3, the latter being shouldered and threaded to this end, substantially as indicated in the drawings. Said main cylinder is further provided, at its rear end, with a nozzle 4, interiorly threaded to receive the end of a flexible tube, or other appropriate connection, whereby, and by way of the supply-passage 5, with which said main cyllinder is provided, a suitable power-medium, preferably air 4under pressure, may be conducted from any appropriate source of supply and delivered to and into the distribution chamber 6, situated within the main cylinder 2.

7 denotes a subsidiary cylinder, 'firmly disposed medially within the main cylinder 2, and cut away centrally and circun'i'lfercntially thereof, substantially as shown in the drawings, to form when thus in place and with the adjacent wall of the cylinder 2, the distribution chamber 6 aforenamed; and I prefer IOO IIO

that said subsidiary cylinder be cut away wholly circumferentially, thereby giving to said chamber an annular form and accordingly rendering it co-extensive with the circul'nlerence of said subsidiary cylinder, the latter being provided with a primary inlet port 8 and a secondary inlet port 9, by way of each of whichcommunication is established between the distribution chamber 6 and the interior of the main cylinder 2.

I further make use of a compound, reciprocating, striking-piston, enlarged diametrically midway its length to form a valveshoulder 10, which fits snugly and operates to and 'fro within, the subsidiary cylinder 7, and hence serves in its reciprocating movements, to alternately open and close, and accordingly control, the inlet ports 8 and 9. Said piston is further provided with opposite working-heads 11, 12, situated, respectively, -a suitable distance from, and at opposite sides of, the valve-shoulder 10, and fitting neatly, respectively, the bore of the main cylinder 2, thereby forming the cornpound, primary expansion chambers 13, 14, which essentially intercommunicate, and

preferably by Way of an axial passage 15, in-

tersected by one ,or more lateral passages 16, all here shown as being formed in said piston, though the same may be otherwise arranged, as in the wall of the chamber 2, in practice.

' The head 12, tting snugly in the bore of the cylinder 2, and the valve-shoulder 10, fitting snugly in the subsidiary cylinder 7, form, between them, a secondary expansion chamber 17.

The lmain cylinder 2 is provided with a primary exhaust port 18, Jior the exhaust from the chamber 14, and with a secondary exhaust port 19, for the exhaust from the chamber 17, both of said exhaust ports being here shown as communicating with a common exhaust passage 20, formed in the wall of the main cylinder 2, extending rearwardly therealong, and terminating in a eneral exhaust port 21, at the rear end o thev main cylinder 2.

Exhaust ports 18 and 19 are alternately opened and closed and hence accordingly controlled, by the piston-head 12, under the reciprocating movements of the latter, and inversely to the opening and closing of the inlet ports 8 and 9 by the valve-shoulder 10; that is, said valve-shoulder and the istonhead 12 bear such relation, in their isposition, each to the other, that'when the former o ens the primary inlet-port and accordingly c oses the secondary inlet-port, the latter, .said piston-head, opens the secondary exhaust ort and closes the primary exhaustport, t e piston, as a whole, occupying, undersuch conditions, substantially the position indicated in Fig. 1 of the drawings; and when valve-shoulder 10 shall have opened the secondary inlet-port, as 9, and closed the primary inlet-port, as 8, the piston-head 12 will have opened the primary exhaust port, as 18, and closed the secondary exhaust port, as 17, the piston as a whole, having moved into substantiallyvthe position indicated in Fig. 2 of the drawings, and which alternate opening and closing oi the respective inletports and the respective exhaust ports, and the control of said inlet-ports inversely, as stated, with respect to the exhaust ports, or vice versa, normally continues under the reciprocating action o'l" said piston. Hence, in my improved pneumatic tool the use of valves, as distinct operative parts, for controlling the respective inlet and exhaust ports, is obviated, the construction as a whole being accordingly much simpliiied, and the cost of producing it being much reduced.

It will be understood that a plurality of inlet-ports, arranged as primary and secondary, and substantially as indicated in the dra-wings, may be availed of at suitable intervals circumferentially of the subsidiary cylinder 7 and this applies, also, to the exhaust ports 17 and 18 with respect to the main cylinder 2.

The threaded opening at the nozzle 4 may be reduced, continued inwardly and threaded, to permit access to the interior of the cylinder 2 for any required purpose, vas for forcing out or removing the subsidiary cylinder 7, the latter being inserted in place within the cylinder 2 under strong pressure 3 and a threaded plug, as 22, or otherappropriate device, may be availed of for normally closing the continued portion of said opening, said plug having a squared, or otherwise suitably shaped recess at its outer end, and as indicated in dotted lines in Fig. 2, to facilitate adjustment of said plug as may be required.

To facilitate the adjustment of the subsidiary cylinder 7, relatively with respect to the striking piston aforenamed, the same may be formed in two or more' segments, as indicated in Figs. 5 and 6. The striking- `piston aforenamed is' provided at its iront end with a striker 23, adapted, at each forward thrust of said piston, to impinge upon and deliver a powerful blow to, any appropriate object, as a rivet, or the shank, as 24, of y a working tool, as a chisel. However, where the object to be acted upon is the shank, as 24, of a working tool, it is desirable that means be provided whereby the same may be loosely held in axial alinement lwith said striker, and in position to receive blows from the latter; and to this end I provide the chuck or nose-piece 3, aforenarned, the same, by preference, taking the general character of a cylinder open at both ends, and the main outer ortion of Whose bore is somewhat lar er 1n diameter than the shank of the tool to t e acted upon, and is reduced somewhat near its4 inner end to form a shoulder 25,l against which, in practice, the adjacent end IOC of the tool-shank may abut, .all as clearly illustrated in Fig. 2 of the drawings.

it is further desirable that means be pro- .vided for preventing reverse turning of the the plane of the threads of said nose-piece,

said opening` serving to receive a key 27, which binds at its inner end on one or more of the threads'of said nose-piece, all as clearly illustrated in Fig. 2. Again, under the shocks imparted to the shank 24, in the prac-tical operation of the device as a whole, sai d key might occasionally become loosened, and to insure a binding effect thereby, even un der this condition. thereof, on the threads of said nose-piece, and in any event a due adjustment, at all times, of the latter with respect to the cylinder 2, l provide an elastic connection 28, here shown as taking the form of a spiral spring, the same being attached at one of its ends to the protruding or outer end ,of the key 27, extending therefrom partially around the nose-piece 3, and connected, in any appropriate manner, as through the medium of a pin 29 to the said nose-piece, at any point desired circumferentially thereof, and tending at all times to exert an elastic force thereon in the direction to turn the same homeward. Observing now, and which should be clearly apparent from the foregoing description. of my improved device, that the striking-piston afcrenamed is self-acting in controlling the respective inlet-ports and the respective exhaust ports, in the manner hereinbefore stated, the operation of the device may be described as follows: The piston having assumed, say, the position indicated. in Fig. 1, a suitable power-medium, preferably air under-pressure, is admitted to the distribution-chamber 6, by way of the main supplypassage 5 and nozzle 4, from which distribution-chamber said power-medium gains entrance, by way of primary inlet-port S, which 4is new open, into the expansion chambers 13 and 14, by way of the passage, as 15 and its branch or branches 16, whereby communication is had between said chambers 13 and 14, said power-medium practically entering both of said chambers simultaneously by reason of its pressure; whereupon it simultaneously acts on both of the faces 30 and 31, of the heads 11 and 12, respectively, and powerfully, by reason of the increased effective area which the combined faces 30, 31, present thereto, thrusts said piston. forward, thereby causing its striker 23 to accordingly strike and. deliver a powerful blow to, any suitable object, as the tool-shank 24. The piston now having assumed the position indicated in Fig. 2, and chambers 13 and 14 having been accordingly exhausted, as by way of the primary exhaust port 18, which is now open, the power-medium gains entrance to the secondary chamber 17, by way of secondary inlet-port 9, which is now open whereupon it acts on the innerface of the piston-head. 12, thereby returning said p iston to the position indicated in Fig. 1, the effective area of the face last referred to being of sufficient area for this purpose. Secondary exhaust being now open, that is, the exhaust port denoted by the numeral 19, the chamber` 17 is exhausted, and said piston is in readiness for another thrust forward, in the manner first above described, and so on, the striking-piston reciprocatingwith great rapidity, and the power-medium being accordingly admitted into and exhausted from the respective chambers 13, 14 and 17.

It will be seen that my present improved pneumatic tool it 'particularly well adapted for the purposes for which it is intended, and further that the same may be modified to a considerable extent, particularly as regards the location of the passage whereby communication is established between the respective chambers 13 and 14, and other details of the general construction, without materially departing from the spirit and principle or my invention.

Having thus fully described vmy invention, what I claim and desire to secure by Letters Patent is:

1. A device of the class herein described comprising a main cylinder, a subsidiary cylinder therein and forming circumferentially therewith a power medium distributionchamber, said main cylinder having a supply-passage communicating with said distri- IOO bution-chamber, and primary and secondary i and the interior of said main cylinder, and a compound, striking-piston, the latter reciprocating within said main cylinder, and controlling the inlet-ports alternately, the exhaust ports alternately, and the inlet-ports inversely to the exhaust ports, substantially as herein specified.

2. A device of the `class herein described comprising a main cylinder; a subsidiary cylinder therein andgforming circumferentially therewith-a distribution-chamber, said main cylinder having a supply-passage communicating with said distribution-chamber; a striking-piston, the same reciprocating within the main cylinder and having a medial .yalve-shoulder, working within said subsidiary cylinder, and working-heads at opposite sides of said valve-shoulder, said heads operating respectively within the bore of the main TIO cylinder and forming expansion chambers, one at the rear oi eachof said heads, said chambers being at all times 1n communication each with the other; an inlet-port whereby communication is established between said distribution-chamber and said communicating expansion chambers, said inlet-port being controlled by said valve-shoulder, and an exhaust port, whereby said communicating expansion chambers are exhausted, said exhaust port being controlled byone of the heads ofA said piston, alternately with the control of said inlet-port by said valve-shoulder,

. substantially as herein speci'Iied.

3. A device of the class herein described comprising a main cylinder; a subsidiary cylinder r"therein and forming circumferentially therewith a distribution-chamber, said main cylinder having a supply-passage communicating with said distribution-chamber; a striking-piston, the same having a medial valveshoulder, working within said subsidiary cylinder, and a head, the latter working Within the bore of the .main cylinder and forming at the front face thereof a secondary expansion chamber an inlet-port, whereby communication between said distributionchamber and said secondary expansion chamber is established, said inlet-port being controlled by said valve-shoulder, and an exhaust port, whereby said secondary expansi on chamber is exhausted, said exhaust port being controlled by said piston-head alternately with the control of said inlet-port by said valve-shoulder7 substantially as herein specified.

4. A device of `the class herein described comprising a main cylinder; a segmental, subsidiary cylinder therein and 'forming circumferentially therewith a distributionchamber, said main cylinder being provided with a supply passage communicating with said distribution-chamber, and provided with one or more inlet-ports, whereby communication is established between said distribution-chamber ,and the interior of said main cylinder, the latter being provided with suitable' exhaust ports; and a compound, striking-piston, the latter reciprocating within said main cylinder and said subsidiary cylinder, and being self-acting in controlling said inlet-ports, substantially as herein specified.

5. A device of the class herein described comprising a main cylinder; a subsidiary cylinder therein, said subsidiary cylinder being cut away circumferential] y to form with the adjacent interior wall of said main cylinder, a power-medium distribution chamber, and being provided with primary and secondary inlet-ports whereby communication is established between said distribution chamber and the interior of said main cylinder, the latter being provided with a powermedium passage communicating with said distribution chamber; and a compound striking-piston, the latter reciprocating within said main cylinder and the subsidiary cylinder, and being self-acting in controlling said primary and said secondary inlet-ports, substantially as herein specified.

6. A device of the class herein described comprising a main cylinder having its bore threaded at the forward end thereof; a nosepiece, threaded and engaging the threads in ysubstantially as herein speciiied.

` CHARLES W. MEADOWUROFT, sii.

Witnesses:

WILsoN STEARLY, CHARLES WILLIAM Mainowcnoir, Jr. 

